A sudden, rapid rise of water in a normally dry or low-flow area, typically caused by intense rainfall over a short period, dam or levee failure, or the sudden release of water from an ice jam. Flash floods develop within minutes to a few hours of the triggering rainfall, giving little warning time, and their fast-moving water is a leading cause of weather-related deaths, particularly among people caught in vehicles or slot canyons.
Facts
PeriodicityNo fixed season; most often occurs in dry areas that have recently received heavy precipitation, though flooding can appear anywhere downstream of the rainfall, even many miles from where it fell. 1 ScaleAs little as 2 feet (0.61 meters) of moving water is enough to sweep away most SUV-sized vehicles; more than half of flash flood deaths are people swept away in vehicles trying to cross flooded intersections. 1 Open Questions
First DescribedNo single first scientific description found in the source consulted.
No source found naming who first scientifically described or classified flash floods; the Wikipedia article gives the Johnstown Flood of 1889 as an early notable dam-failure example, not a first scientific description, checked this pass. Identification
Distinguishing AppearanceA rapid flooding of low-lying areas such as washes, rivers, dry lakes and depressions, caused by heavy rain, storm systems, snow or ice meltwater, or the sudden collapse of a natural or man-made dam; distinguished from an ordinary flood by striking within fewer than six hours of the trigger event. 1 Connections
Associated With
The intense, concentrated rainfall a tropical cyclone delivers is a direct and well-documented cause of flash flooding, both along the coast and far inland as the storm weakens.
Demonstrated By
Source National Oceanic and Atmospheric Administration
Desert, Biomes Source National Oceanic and Atmospheric Administration
Sources
1. Flash Flood (Wikipedia)
WikipediaCauses section (occurrence sentence)
Flash floods most often occur in dry areas that have recently received precipitation, but they may be seen anywhere downstream from the source of the precipitation, even many miles from the source.
Hazards section (vehicle-depth sentence)
More than half of the fatalities attributed to flash floods are people swept away in vehicles when trying to cross flooded intersections. As little as 2 feet (0.61 m) of water is enough to carry away most SUV-sized vehicles.
lead section
A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes, and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, or tropical storm, or by meltwater from ice and snow. Flash floods may also occur after the collapse of a natural ice or debris dam, or a human structure such as a man-made dam, as occurred before the Johnstown Flood of 1889. Flash floods are distinguished from regular floods by having a timescale of fewer than six hours between rainfall and the onset of flooding.
View the Source National Oceanic and Atmospheric Administration
National Oceanic and Atmospheric Administration- Demonstrated By: Desert
- Demonstrated By: Chihuahuan Desert
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